Engines used in automotive and other applications may be mounted to a transmission using an adapter between the engine and transmission that provides both a means to connect the dissimilar mounting surfaces of the engine and transmission and also a space to enclose a clutch or similar coupling device to transfer the rotational movement from the engine crankshaft to the transmission. An engine typically has a crankshaft that extends longitudinally through the engine with a mounting surface located at the rear of the engine to which a flywheel, flex plate, or similar torque transfer mounting surface is affixed. The crankshaft has a rotational center (axis of rotation) which is determined by the characteristics of the crankshaft and the engine bearings within which the crankshaft rotates. The description herein may make references to a clutch, a flywheel, and a transmission. One ordinarily skilled in the art will appreciate that the embodiments are also applicable to engine/transmission combinations that utilize automatic transmissions with torque converter devices and flex plates and also embodiments in which the engine crankshaft is connected directly to the transmission rather than through the use of clutches and flywheels as discussed herein.
A transmission generally comprises an input shaft which is placed in rotational communication with a clutch/flywheel assembly affixed to the crankshaft of the engine. Failure to align the rotational axis of the crankshaft with the rotational axis of the transmission input shaft can cause damage to the bearings located at the transmission input shaft and at other locations in the transmission. The more severe the misalignment, the greater the potential damage to the transmission and corresponding reduction in service life. Therefore, minimizing the amount of such misalignment is critical when mounting a transmission to an engine. As was noted above, the interface between the engine and the transmission may be bellhousing. Many bellhousings have a circular opening formed in the transmission mounting surface through which the transmission input shaft is passed when the transmission is installed on the bellhousing. In many such bellhousings, these circular openings are formed such that their center points are oriented a known distance from transmission locating dowels. These dowels serve to align the shaft of the transmission with the center point of the opening. In order to align the bellhousing opening with the crankshaft of the engine and thus the transmission input shaft with the crankshaft, a measurement fixture may be attached to the crankshaft and used to alight the bellhousing opening. This fixture may comprise a shaft extending from the crankshaft to which a measurement device such as a dial indicator is mounted. The measurement device is used to indicate changes in alignment as the crankshaft is rotated. If the bellhousing is misaligned, the measurement may be greater at one point of rotation then at another. A user may adjust the mounting of the bellhousing to minimize the variation of the measurement as the crankshaft is rotated through 360 degrees. Other alignment fixtures may rely on a disc structure that is affixed to the crankshaft which occupies the bellhousing opening to indicate that the opening is aligned with regard to the crankshaft. Certain bellhousing configurations, in order to properly interface with certain types of transmissions, do not have a circular opening as previously described. An example of such a transmission is a Tremec T56 (“T56”) transmission. In this particular transmission style, the bellhousing mounting opening is required to be roughly a large circle in shape but also includes several irregular portions. The result is that the inner surface of the transmission mounting surface of a bellhousing intended for this type of transmission will not have a circular shape usable by the alignment measurement fixture previously described, but instead may have an irregular, non-circular, non-concentric or overly large opening which is not suitable for use with an alignment tool. As a result, someone attempting to mount a T56 transmission may be required to disassemble the transmission in order to use a front panel portion of the transmission case to create the round opening needed for proper alignment of the crankshaft and transmission input shaft. As a result, having to disassemble the transmission in order to utilize the transmission front panel creates a great deal of additional work for someone wishing to perform the alignment of the engine and transmission.
What is needed is a device for facilitating the alignment of an engine crankshaft and transmission input shaft when the bellhousing opening is such that a conventional alignment fixture will not perform correctly. In an embodiment of the invention, an alignment plate is created such that the alignment plate provides a circular opening positioned at a precise distance from transmission locating pins located in the bellhousing. This alignment plate permits a user of the plate to align a bellhousing using standard alignment fixtures without the need to provide a transmission housing portion to perform the alignment as described above.
Further features and advantages of the devices and systems disclosed herein, as well as the structure and operation of various aspects of the present disclosure, are described in detail below with reference to the accompanying figures.